By the definition on the textbook, If the testicle didn't drop into the scrotum by 8 weeks. We can call it cryptorchid. However, the testicle still could have a chance to drop into scrotum by 6 months old. So, if you cann't feel 2 little nuts inside the scrotum and your dog is over 2 months old, the dog could have "Cryptorchid"